Resistorless Frequency Locked On-Chip Oscillator with Proportional-to-Absolute Temperature References

摘要

A 36-kHz frequency locked on-chip oscillator is proposed, the proportional-to-absolute temperature (PTAT) current and voltage generator is presented to eliminate conventional temperature-compensated resistors. The resistorless approach reduces the process variation of frequency and the chip area. The oscillator is fabricated in 0.18-pm standard CMOS process with an active area of 0.072 mm(2). The temperature coefficient of frequency is 48 ppm/degrees C at best and 82.5 ppm/degrees C on average over -40-70 degrees C and the frequency spread is 1.43% (sigma/mu) without calibration. The supply voltage sensitivity is 1.8%/V in the range from 0.65 V to 1 V and the power consumption is 95 nW under the supply voltage of 0.65 V.